Timing device

ABSTRACT

A pneumatic timing device in which a timing head includes an air chamber, a diaphragm is movable relative to the timing head to effect a change in the volume of the air chamber and establish a flow of air into or out of the air chamber, a timing member is coupled for movement with the diaphragm at a rate determined by the rate of flow of air to or from the air chamber, a passage in the timing head communicates with the air chamber for conducting the flow of air, a body of porous material is in the passage for throttling the flow to a predetermined maximum rate of flow, the body of porous material having a surface of prescribed area through which the air flow passes, and a shutter is in close engagement with the surface of the body of porous material and includes a relatively non-porous member selectively movable along the surface relative to the body to close off at least portions of the area to the air flow for selectively varying the rate of the flow to regulate the rate of movement of the timing member.

United States Patent 91 Flanagan et al.

[541 TIMING DEVICE [75] Inventors: Robert M. Flanagan; Glenn W.

Johnson, both of Summit, NJ.

[73] Assignee: Amerace Esna Corporation, New

York,N.Y.

[22] Filed: July 19, 1971 21 Appl. No.: 164,062

Related US. Application Data [62] Division of Ser. No. 802,546, Feb. 26,1969, Pat. No.

[ Jan. 16,1973

Primary ExaminerHarold Broome Attorney-Samuelson & Jacob [57] ABSTRACT Apneumatic timing device in which a timing head includes an air chamber,a diaphragm is movable relative to the timing head to effect a change inthe volume of the air chamber and establish a flow of air into or out ofthe air chamber, a timing member is coupled for movement with thediaphragm at a rate determined by the rate of flow of air to or from theair chamber, a passage in the timing head communicates with the airchamber for conducting the flow of air, a body of porous material is inthe passage for throttling the flow to a predetermined maximum rate offlow, the body of porous material having a surface of prescribed areathrough which the air flow passes, and a shutter is in close engagementwith the surface of the body of porous material and includes arelatively non-porous member selectively movable along the surfacerelative to the body to close off at least portions of the area to theair flow for selectively varying the rate of the flow to regulate therate of movement of the timing member.

4 Claims, 8 Drawing Figures PATENTEDJAHI 6 ms SHEET 1 [IF 4PATENTE-nJAnlslsrs 3 711 797 SHEET 2 OF 4 PATENTEDJAH 16 I975 SHEET 3 BF4 'nMiNG onvrca to provide a time delay period between the activation'of the timing device and the actuation of a control,

such as, for example, an electrical switch. In such timing devices, atiming member generally effects the control function and the rate ofmovement of the timing member is determined by the rate of flow of afluid, such as air, through a passage communicating with a chamber ofvariable volume. These timing devices are usually selectively adjustableso as to provide a desired time delay period, the duration of which maybe selectively varied within a prescribed range. A variety of mechanismshave been employed for selectively adjusting or dialing the duration ofthe time delay period. Various valving arrangements have been used, suchas needle valves, but such valving arrangements have been found to beunreliable in that accurate adjustments are difficult to execute, dialadjustments are usually not related to the corresponding time intervalsin a linear fashion and the dial settings vary from device to device sothat standardization is difficult to achieve.

One type of adjustable mechanism which has been successful in attaininguniformity and which has achieved a linear relationship between dialsettings and corresponding timed intervals employs a timing groovethrough which air flows and which may be varied in length to vary therate of air flow and thus vary the duration of the timed interval. Sucha mechanism, while attaining uniformity of operation, has been foundexpensive to manufacture in view of the close tolerances which must bemaintained in the fabrication of component parts of the mechanism.

It is therefore an important object of the invention to provide a timingdevice having an adjustable time delay mechanism which is relativelyinexpensive to manufacture, yet provides uniformity of adjustment and aneasily repeatable relationship between increments of adjustment andincrements of change of the duration of the interval of the time delay.

Another object of the invention is to provide an inexpensive timingdevice wherein the duration of the timed interval may be selected byoperation of a dial having a scale which bears a linear relationshipwith the actual duration of the timed interval.

Still another object of the invention is to provide an inexpensivetiming device wherein the duration of the timed interval of the timedelay mechanism may be varied over a prescribed range and wherein thatrange may be changed readily with minimal effort.

A further object of the invention is to provide a timing device having aconstruction which allows ready calibration of the time delay mechanismso as to attain uniformity of operation from device to device.

A still further object of the invention is to provide a timing devicehaving a minimum number of component parts, each of which is easilyfabricated and each of which may be manufactured without the necessityof maintaining close tolerances in highly critical dimensions so as toreduce the cost of manufacture.

The above objects as well as further objects and advantages are attainedby the invention which may be described briefly as a timing devicewherein the movement of a timing member effects a control function andthe rate of movement of the timing member is determined by the rate offlow of a fluid, such as air, through a passage communicating with achamber of variable volume, means for selectively regulating the rate offlow of the fluid through the passage to vary the rate of flow between apredetermined maximum rate and a minimum rate, the regulating meanscomprising a body of porous material in the passage for throttling theflow to approximately the order of magnitude of the maximum rate offlow, the body of porous material having a surface of prescribed areathrough which the flow passes, shutter means juxtaposed in closeengagement with the surface, and the body of porous material and theshutter means being selectively movable relative to one another to closeoff at least portions of the area to the flow for selectively varyingthe rate of flow to regulate the rate of movement of the timing member.Means may be provided for allowing ready access to the body of porousmaterial so that the body may be selectively removed and replaced with asimilar body of different porosity to change the order of magnitude ofthe maximum rate of flow.

The invention will be more fully understood and still further objectsand advantages thereof will become apparent in the following detaileddescription of an embodiment of the invention illustrated in theaccompanying drawing, in which:

FIG. 1 is a plan view of a pneumatic timing device constructed inaccordance with the invention;

FIG. 2 is an enlarged cross-sectional view taken along line 22 of FIG.1,

FIG. 3 is a fragmentary cross-sectional view illustrating the componentparts of the device of FIG. 2 in another operating position;

FIG. 4 is a fragmentary cross-sectional view illustrating the componentparts in another operating position;

FIG. 5 is a fragmentary cross-sectional view illustrating the componentparts in still another operating position;

FIG. 6 is a cross-sectional view taken along line 66 of FIG. 2;

FIG. 7 is a cross-sectional view similar to FIG. 6 showing the componentparts thereof in another selected position; and

FIG. 8 is a cross-sectional view similar to FIGS. 6 and 7 but showingthe component parts in still another selected position.

Referring now to the drawing, and especially FIGS. 1 and 2, a time-delaycontrol apparatus 10 is shown to comprise a base 12, which isadvantageously fabricated from a dielectric material, and upon which ismounted a solenoid assembly 14. The solenoid assembly comprises a frame16 in which is found the usual coil 18 and armature 26. The terminals ofthe coil are connected to insulated electrical conductors 22 which are,in turn,

connected to a rectifier 24 mounted on the base 12 and having inputterminals 26 passing through the base for external connection. Since,insofar as the present invention is concerned, the specific type orconstruction of the solenoid assembly is not critical, any suitableconstruction of known kind may be employed to accommodate the voltageand type of current available for its energization.

A pneumatic timing device is shown in the form of a timing head 28including a timing member illustrated in the form of a rod 30 whichpasses through the armature and is reciprocatable independent of themovement of the armature. Rod also passes through a bushing 32 which isaffixed to the solenoid frame 16 adjacent the upper end of the coil 18.The rod 30 is connected at its upper end 34 to a diaphragm assembly 36which includes a flexible diaphragm 38 which is clamped at its peripherybetween an upper housing member 40 and a lower housing member 42 so asto establish a timing chamber 44 having an upper chamber portion 46 forcontaining a fluid such as air between the diaphragm 38 and the upperhousing member 40 and a lower chamber portion 48. v

' Intermediate the ends of the rod 30 there is an annular groove 50 inthe rod which is engaged by a forked control arm 52 of an overcentertype snap-action electrical switch 54 mounted upon the base 12. Theovercenter snap-action electrical switch has a pair of fixed electricalcontacts 56 and 58 between which a support member 60 carries a movablecontact 62 in such a way that the support member 60 may be actuated tobring the movable contact 62 into electrical contact with either one orthe other of the fixed contacts. Traverse of the movable contact'62 isaccomplished by movement of the arm 52 which is coupled to the movablecontact support member 60 by means of a U-shaped over-center spring 64.The terminals 66 of the electrical switch 54 extend through the base 12so as to enable external connections to be made to the switch. [n theoperating position shown in FIG. 2, 'a shoulder 68 on the rod 30 isurged into engagement with the bushing 32 of the solenoid assembly 14 bymeans of a helical spring 70 which is located in a recess 72 in thebushing 32 and which urges the armature 20 downwardly and intoengagement with a collar 74 retained at the lower end 76 of the rod 30by means of a retaining ring 78. In this position the actuating arm 52of the electrical switch 54 is in its downward position and the movablecontact 62 is urged upwardly by the over-center spring 64 intoengagement with the upper fixed contact 56.

The flexible diaphragm assembly 36 includes the diaphragm 38 fabricatedof a flexible material, preferably an elastomer, which has a head 80molded around its outer periphery and secured between upper and lowerhousing members 40 and 42. A relatively rigid annular. member 82 isaffixed within a central aperture 84 of the diaphragm 38 and carries anannular valve member 86 which is also preferably fabricated of anelastomer and has a lowermost surface 88. The uppermost end 34 of therod 30 passes through a tubular extension 9001 the annular member 82 anda helical spring 92 extends between a retainer 94 carried by the rod 30and the annular member 82 so as to urge the annular member downwardlyuntil the lower surface 88 of the valve member 86 engages a valve seat96 on the rod 30 to close off any pathway for air between the upper andlower chambers 46 and 48 through the diaphragm assembly 36.

When the coil 18 of the solenoid is energized by an operator or someautomatic means, the armature 20 is drawn vertically upwardly into thecoil against the force of the helical spring until a flange 100, whichis located at the lowermost portion of the armature 20, comes intoabutment with the solenoid frame 16, as seen in FIG. 3. A furtherhelical spring 102, which has been in compression up to this time, isnow permitted to move the rod 30 vertically upwardly since the upwardmovement of the armature will free the collar 74 for upward movement.However, such upward movement of the rod 30 is restrained by thepressure of the air in the upper timing chamber portion 46 actingagainst the upward deflection of the flexible diaphragm 38.

The air in the upper chamber portion 46 is thus forced by the upwardmovement of the diaphragm assembly 36 to pass through a passage 104 inthe upper housing member 40, the passage 104 including a portion 106which communicates with a recess 108 in 'which there is seated a body ofporous material shown in the form of a block of porous metal in the formof a disk 110 placed within a solid rim 111 and having an upper surface112 which is flat and which is urged upwardly by a resilient O-ring 114pressed against rim 111. The O-ring 114 forms an air seal at the areasof contact between the O-ring 114, the rim 111 and the recess 108 sothat any flow of air through the recess 108 must pass through an opening115 in the rim and through the porous disk 110. The upper housing member40 isitself provided with a flat or planar surface 116 at the topthereof and a dial 118 is mounted for rotation upon the upper housingmember by means of a screw 120 which passes through the dial and intothe upper housing member. Shutter means of relatively non-porousmaterial are shown in the form of a relatively thin resilient shuttermember 122 which is in the form of a disk affixed to the dial 118 forrotation therewith, preferably by an adhesive, and includes a channel124 therein (also see FIG. 6). Shutter member 122 is fabricated of anair-impervious elastomer and establishes an air seal where the flatsurface 116 is engaged by the shutter member. The upper housing member40 has an annular groove 126 therein which communicates with the lowerchamber portion 48 through a further passage portion 128 whichinterconnects the annular groove 126 with the lower chamber portion. Anotch 130 in the shutter member 122 interconnects the channel 124 withthe annular groove 126 such that the air which is forced from the upperchamber portion 46 through the passage portion 106 and into the recess108 may pass through the porous metal disk 110 and the portion of thechannel 124 which is juxtaposed therewith, across the notch 130 and intothe annular groove 126 to be directed to the passage portion 128 and tothe lower chamber portion 48. Since the porous metal disk 110 willpresent a certain amount of resistance to the passage of the airtherethrough the flow of air out of the upper chamber portion will beimpeded and restricted to a prescribed rate which, in turn, willrestrict the upward movement of the rod 30 to a prescribed rate. Theupward movement of the rod will move the actuating arm 52 of theelectrical switch 54 upwardly until, after the lapse of a prescribedperiod of time, rod 30 will reach the position shown in FIG. 4, the biasof the over-center spring 64 will be reversed-and the movable contact 62of the electrical switch 54 will be driven from engagement with theupper fixed contact 56 into engagement with the lower fixed contact 58.

Upon-de-energization of the solenoid coil 18 the helical spring 70 willurge the armature 2i) downwardly and since the flange portion 100 of thearmature 20 is in engagement with the collar 74 carried by the rod 30,the rod will be urged downwardly against the bias of the helical spring102. As best seen in FIG. 5, the downward movement of the rod 30 willtend to draw the diaphragm assembly 36 downwardly and in so doing willallow the helical spring 92 to compress until the retainer 94 at theupper end 34 of the rod 341 is seated upon the tubular extension 90 ofthe annular member 82 and the valve seat 96 is drawn away from the valvemember 86 to enable air to pass from the lower chamber portion 48through perforations 140 in the tubular extension 90 of the annularmember and into the upper chamber portion 46, as indicated by the"arrows in FIG. 5, with relatively little resistance so that the downwardmovement of the rod 31) and the diaphragm assembly 36 after deenergization of the solenoid is practically instantaneous.

The rate at which the rod 30 moves in the upward direction may beregulated by regulating the rate of flow of air from the upper chamberportion 46 to the lower chamber portion 48 during the upward movement ofthe rod and the diaphragm assembly as described above. Turning now toFIGS. 6, 7 and 8, it will be seen that the channel 124 of the shuttermember 122 extends along an arcuate path and has a length which isgreater than the diameter of the disk 110 of porous metal so that as thedial 118 and the shutter member 122 are rotated, the shutter member willslide over the flat surface 116 and different portions of the channel124 are brought into juxtaposition with the porous metal disk 110. Sincethe channel varies in width from end to end, as the dial and the shuttermember are rotated, the exposed area of the porous metal disk is variedto vary the amount of air which may pass through the disk and thus varythe rate of flow of air out of the upper chamber portion 46. Thus, asseen in FIG. 6, a relatively large area 142 of the porous metal disk 110is exposed, thereby permitting air to flow rather rapidly through thedisk 110, into the groove 126, and through passage portion 128 into thelower chamber portion 48. When the dial 118 and shutter member 122 areturned through a 90 displacement, as seen in FIG. 7, a lesser area 144of the disk of porous metal is exposed while other areas 146 of the diskare closed to any flow of air by virtue of the surface 112 of the disk 1being urged against the shutter member 122 to seal off those areas 146and the rate of flow of air from the upper chamber portion through thedisk and into the channel 124 and through the notch 130 into the groove126 and subsequently into the passage portion 128 and to the lowerchamber portion will be lower than the rate of flow of air when the dialand shutter member are in the position shown in FIG. 6. Likewise, whenthe dial and shutter member are further rotated through an additional 90displacement, as seen in FIG. 8, an even lesser area 148 of the surface112 of the disk is exposed and the rate of air flow is decreased evenmore. Thus, the porous metal disk 110 serves to throttle the air flow toapproximately the order of magnitude of the maximum rate of flow whilethe configuration of the channel 124 in the shutter member enables theair flow to be regulated over a range between the predetermined maximumrate and a minimum rate.

When it is desired to change the order of magnitude of the maximum rateof flow, it becomes a relatively simple matter to merely remove thescrew 120 to thereby allow removal of the dial 118 and the shuttermember 122 to expose the disk 110 which may then be removed from therecess 108 and replaced with any one of a variety of disks havingdifferent degrees of porosity. The disks are preferably fabricated ofporous metal and the porosity of such disks may be easily controlled inthe fabrication thereof. Sintered metal disks of varying degrees ofporosity are easily fabricated for this purpose.

As seen in FiG. 1, the dial 1 18 may be provided with a scale 150 whichis calibrated in accordance with the configuration of the channel 124 sothat a visual alignment of a portion of the scale with a pointer 152(also see FIG. 2) will give a true reading of the duration of the timeinterval between activation of the solenoid and the actuation ofelectrical switch 54 by movement of rod 30 through the requireddisplacement.

Although channel 124 has a configuration which provides a linearrelationship between increments of displacement of the dial and shuttermeans and corresponding increments of change in the duration of the timedelay interval, it will be apparent that different configurations may beprovided in channel 124 where other relationships are desired.

It is noted that the air in the timing device is circulated andrecirculated between the upper and lower chamber portions 46 and 48 sothat a constant volume of air remains in chamber 44. Thus, no outsideair need be introduced into the timing device and a high level ofcleanliness may be maintained within the chamber 44. Such cleanlinesswill enhance the accuracy of the device.

Returning now to FIG. 2, it will be seen that the actuation of theelectrical switch 54 takes place at the point where the bias of theover-center spring 64 will be reversed and will therefore take placeafter the lapse of the period of time necessary for the rod 30 to movefrom the first position shown in FIG. 2 upwardly to a second positionwhere the bias of the over-center spring will be reversed. Since theduration of that period is directly related to the amount ofdisplacement of the rod 30 prior to the time when the rod reaches thesecond position where the bias of the over-center spring will bereversed, it will be seen that small variations in the magnitude of thatdisplacement will produce corresponding variations in the actualduration of the timed interval. Therefore, when it is necessary tocalibrate the time delay control apparatus so as to correlate the actualduration of the timed interval with the scale appearing on the dial 118(see FIG. 1) the device incorporates means for allowing adjustment ofthe initial position of the rod 30 with respect to the actuating arm 52as seen in FIG. 2. Thus, the solenoid frame 16 is affixed to the base 12by means of a bracket 160 and a pair of mounting screws 162 which passthrough slots 164 in the base. Bracket 160 is integral with the frame 16and extends through the base 12 to a mounting pad 166 (see FIG. 1) whichis provided for mounting the bracket and the apparatus upon an externalstructure. By loosening the screws 162 the bracket 160 may be movedupwardly or downwardly with respect to the base 12, such displacementbeing permitted by the slots 164, thereby moving the bushing 32, whichis in fixed assembly with the frame '16, upwardly or downwardly. Sincethe bushing 32 cooperates with the shoulder 68 of the rod 30 to serve asa stop member which defines the first position of the rod 30, suchupward or downward movement of the bushing 32 will change the firstposition of the rod 30 and especially the position of the annular groove50 in the rod with respect to the dead-center position of theover-center snap-action electrical switch 54 thereby enabling slightadjustments in the displacement of the rod 30 necessary to actuate theelectrical switch.

in addition, the integral construction of the bracket 160 and solenoidframe 16 permits rapid dissipation of heat from the solenoidcoil byfabricating the bracket and frame of a heat conductive material. Thus,heat generated during operation of the solenoid coil may be carried outof the apparatus 10 and dissipated in surrounding structures to whichthe apparatus is attached, thereby enabling a compact construction whichwill operate effectively and reliably over extended periods of time.

The above detailed description of an embodiment of the invention ispresented by way of example only. Various details of design andconstruction may be modified without departing from the true spirit andscope of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A pneumatic timing device comprising:

a base;

a timing head including an air chamber mounted upon said base;

means movable relative to said timing head to effect a change in thevolume of the air chamber and movement of air into or out of thechamber;

a timing member coupled for movement with said movable means along apath of travel between first and second positions at a rate determinedby rate of flow of air to or from the chamber;

a bracket for mounting said base upon an external structure;

a control arm mounted upon said base for movement in response tomovement of said timing member through a prescribed displacement fromone of said first and second positions to actuate a control means;

a stop member carried by said bracket and abutting a portion of thetiming member when said timing member is at said one of said positions;and

means mounting said base upon said bracket for selective adjustment ofthe relative position of the base and bracket to enable adjustment ofthe position of the stop member relative to the control 2. T l iepneumatic timing device of claim 1 including:

a solenoid;

means coupling said solenoid with said timing member such that thetiming member moves in response to operation of the solenoid;

a frame upon which the solenoid is mounted, said frame being integralwith said bracket; and

said frame and said bracket being fabricated of a heat-conductivematerial.

3. The timing device of claim 1 wherein said control means includes anelectrical switch capable of being actuated by the control arm as saidcontrol arm is moved in response to movement of the timing member fromsaid one of said positions toward the other of said positions.

4. The timing device of claim 3 wherein said control means includesover-center spring means coupling said control arm with said electricalswitch and arranged such that the bias of the overeenter spring meanswill be reversed as the timing member moves from said one of saidpositions to the other of said positions.

1. A pneumatic timing device comprising: a base; a timing head includingan air chamber mounted upon said base; means movable relative to saidtiming head to effect a change in the volume of the air chamber andmovement of air into or out of the chamber; a timing member coupled formovement with said movable means along a path of travel between firstand second positions at a rate determined by rate of flow of air to orfrOm the chamber; a bracket for mounting said base upon an externalstructure; a control arm mounted upon said base for movement in responseto movement of said timing member through a prescribed displacement fromone of said first and second positions to actuate a control means; astop member carried by said bracket and abutting a portion of the timingmember when said timing member is at said one of said positions; andmeans mounting said base upon said bracket for selective adjustment ofthe relative position of the base and bracket to enable adjustment ofthe position of the stop member relative to the control arm.
 2. Thepneumatic timing device of claim 1 including: a solenoid; means couplingsaid solenoid with said timing member such that the timing member movesin response to operation of the solenoid; a frame upon which thesolenoid is mounted, said frame being integral with said bracket; andsaid frame and said bracket being fabricated of a heat-conductivematerial.
 3. The timing device of claim 1 wherein said control meansincludes an electrical switch capable of being actuated by the controlarm as said control arm is moved in response to movement of the timingmember from said one of said positions toward the other of saidpositions.
 4. The timing device of claim 3 wherein said control meansincludes over-center spring means coupling said control arm with saidelectrical switch and arranged such that the bias of the overcenterspring means will be reversed as the timing member moves from said oneof said positions to the other of said positions.